Probably a routing issue from misconfiguration. If you have a module named "blog", the application could confuse the module with the controller if you're using the path to decide which module to use. If you have two BlogControllers, there could be a module conflict, or perhaps you have a blogAction in your IndexController which it's getting confused with. It could be something as simple as a typo: perhaps your file doesn't match the class name. Or maybe it's a namespace issue.